U.S. patent number 5,735,589 [Application Number 08/571,124] was granted by the patent office on 1998-04-07 for sliding refrigerator shelf assembly.
This patent grant is currently assigned to Donnelly Technology, Inc.. Invention is credited to Robert S. Herrmann, Edmund J. Kane.
United States Patent |
5,735,589 |
Herrmann , et al. |
April 7, 1998 |
Sliding refrigerator shelf assembly
Abstract
A shelf assembly for a refrigerator compartment such as a
refrigerator for food products includes a shelf member slidably
supported for extension and retraction on a shelf support. The
shelf member includes side members which are preferably molded as a
rim on an article support surface from an ethylene-polypropylene
copolymer and include slide surfaces engaging spaced, generally
horizontal and parallel shelf support surfaces preferably formed by
L-shaped brackets on the shelf support. A guide member depends from
at least one, and preferably both, of the side members to guide the
sliding movement. A stop on the guide member limits travel by
engaging a limit surface on the shelf support. The guide member and
stop may be molded integrally with the side members to define a
molded slide channel or formed by a rigid insert embedded in the
rim during molding. The method includes injecting the moldable
around a rigid core positioned in a mold cavity and withdrawing the
core after removing the molded rim to leave a slide channel in the
rim.
Inventors: |
Herrmann; Robert S. (Grand
Haven, MI), Kane; Edmund J. (Holland, MI) |
Assignee: |
Donnelly Technology, Inc.
(Holland, MI)
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Family
ID: |
22890308 |
Appl.
No.: |
08/571,124 |
Filed: |
December 12, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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236629 |
Apr 29, 1994 |
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Current U.S.
Class: |
312/408; 108/102;
108/108; 211/153; 312/334.44 |
Current CPC
Class: |
B29C
33/123 (20130101); B29C 33/442 (20130101); B29C
45/14434 (20130101); B29C 45/4407 (20130101); F25D
25/024 (20130101); F25D 2325/022 (20130101) |
Current International
Class: |
B29C
33/12 (20060101); B29C 33/44 (20060101); B29C
45/14 (20060101); B29C 45/44 (20060101); F25D
25/02 (20060101); F25D 011/00 () |
Field of
Search: |
;312/408,410,404,334.46,334.44 ;108/108,102 ;211/153,151
;248/247,250 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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581419 |
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Feb 1994 |
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EP |
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3431666 |
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Mar 1986 |
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DE |
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4038172 |
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Jun 1992 |
|
DE |
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60-68916 |
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Apr 1985 |
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JP |
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93 23229 |
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Nov 1993 |
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WO |
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Primary Examiner: Cuomo; Peter M.
Assistant Examiner: Wilkens; Janet M.
Attorney, Agent or Firm: Van Dyke, Gardner, Linn &
Burkhart
Parent Case Text
CROSS REFERENCE
This is a continuation of application Ser. No. 08/236,629, filed
Apr. 29, 1994, now abandoned.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A shelf assembly for a refrigerated compartment comprising:
a shelf support including a pair of spaced, generally horizontal,
generally parallel, shelf support surfaces, a guide surface on each
shelf support surface extending at an angle to said shelf support
surface, an undersurface beneath each shelf support surface, and at
least one mounting member adapted to mount said shelf support in a
refrigerated compartment;
a shelf member slidably mounted for extension and retraction on
said shelf support, said shelf member including an article support
surface and a pair of spaced side members, said side members being
molded in one piece on said article support surface from a moldable
material and extending along opposite sides of said article support
surface, each side member including a slide surface slidably
engaging one of said shelf support surfaces, at least one of said
side members having a depending guide member adjacent said slide
surface to guide sliding movement of said shelf member, said one
guide member including a stop thereon, said guide member extending
along said guide surface to limit lateral movement of said shelf
member with respect to said shelf support, said guide member also
including a laterally extending, lift restraining member, said lift
restraining member extending under and immediately adjacent said
shelf support undersurface and adapted to engage said undersurface
in the event said shelf member is lifted to restrict vertical
movement of said shelf member with respect to said shelf support;
and
said shelf support also including an elongated opening for
receiving and allowing movement of said stop when said shelf member
is slidably extended or retracted, and at least one limit surface
for engaging said stop member to limit at least one of the
extension or retraction of said shelf member.
2. The shelf assembly of claim 1, wherein said shelf support
includes a pair of spaced, parallel support brackets, each bracket
having one of said shelf support surfaces and one of said mounting
members thereon.
3. The shelf assembly of claim 2, wherein each of said brackets is
L-shaped and includes a body and a laterally extending flange
extending at a right angle to said body, said flange having a top
surface forming said shelf support surface.
4. The shelf assembly of claim 3, wherein said flanges on said
brackets extend inwardly toward one another.
5. The shelf assembly of claim 3, wherein said one guide member is
a rigid member having one portion embedded within said one side
member and a second portion extending downwardly from said side
member and extending along and under one of said flanges.
6. The shelf assembly of claim 5, wherein said rigid member is a
U-shaped insert embedded in said slide surface of said one side
member.
7. The shelf assembly of claim 6, wherein said insert extends
around an edge of said one bracket flange in the space between said
brackets, said stop including an edge of said U-shaped insert; said
shelf support including at least one cross member extending between
said brackets for spacing and supporting said brackets; said limit
surface including a limit member on one of said brackets and said
cross member for engagement by said edge of said insert.
8. The shelf assembly of claim 5, wherein said rigid member is a
stud embedded in said slide surface of said one side member.
9. The shelf assembly of claim 8, wherein said one bracket flange
includes a slot forming said elongated opening in said shelf
support; said stud projecting into said slot; said slot having at
least one closed end defining said limit surface.
10. The shelf assembly of claim 9, wherein said stud includes
spaced, laterally extending flanges, one stud flange embedded in
said one side member, the other stud flange extending under said
one bracket flange.
11. The shelf assembly of claim 10, wherein said slot includes an
enlarged area for receiving said other stud flange
therethrough.
12. The shelf assembly of claim 2, wherein said shelf support
includes at least one cross member extending between said brackets
for spacing and supporting said brackets; said cross member
including said limit surface; said stop adapted to engage a portion
of said cross member in one position of said shelf member.
13. The shelf assembly of claim 1, wherein said shelf member
includes a generally planar shelf panel having a perimeter edge
thereon, and a rim molded on and circumscribing said perimeter
edge, said rim being molded from a resinous polymeric material and
including said side members; said guide member including a flange
molded in one piece with said rim.
14. The shelf assembly of claim 13, wherein said stop is molded in
one piece with said molded flange on said guide member.
15. The shelf assembly of claim 1, wherein said shelf support is a
frame including a pair of spaced, L-shaped brackets and at least
one cross member extending between said L-shaped brackets for
spacing and supporting said brackets, said brackets each including
a body and a laterally extending flange extending at a right angle
to said body, said flange having a top surface forming said shelf
support surface.
16. The shelf assembly of claim 15, wherein said limit surface is
on one of said brackets.
17. The shelf assembly of claim 15, wherein said limit surface is
on said cross member.
18. A shelf assembly for a refrigerated compartment comprising:
a shelf support including a pair of spaced, generally horizontal,
generally parallel, shelf support surfaces, a guide surface on each
shelf support surface extending at an angle to said shelf support
surface, an undersurface beneath each shelf support surface, and at
least one mounting member adapted to mount said shelf support in a
refrigerated compartment;
a shelf member slidably mounted for extension and retraction on
said shelf support, said shelf member including an article support
surface and a pair of spaced side members, said side members being
molded in one piece on said article support surface from a moldable
material and extending along opposite sides of said article support
surface, each side member including a slide surface slidably
engaging one of said shelf support surfaces, at least one of said
side members having a depending guide member adjacent said slide
surface to guide sliding movement of said shelf member, said one
guide member including a stop thereon, said guide member extending
along said guide surface and under and immediately adjacent said
shelf support undersurface to limit lateral and vertical movement
of said shelf member with respect to said shelf support;
said shelf support also including an elongated opening for
receiving and allowing movement of said stop when said shelf member
is slidably extended or retracted, and at least one limit surface
for engaging said stop member to limit at least one of the
extension or retraction .of said shelf member;
said shelf support including a pair of spaced, parallel support
brackets, each bracket having one of said shelf support surfaces
and one of said mounting members thereon, each of said brackets
being L-shaped and including a body and a laterally extending
flange extending at a right angle to said body, said flange having
a top surface forming said shelf support surface;
said guide member extending along and under one of said flanges on
one of said brackets; and,
said guide member and stop being molded integrally and in one piece
with said one side member.
19. The shelf assembly of claim 18, wherein said one side member
also includes a second guide member molded integrally and in one
piece therewith and spaced from the first said guide member, said
one side member including a molded channel receiving said one
bracket flange and defining said guide members.
20. The shelf assembly of claim 19, wherein said one bracket
includes a limit member thereon, said stop adapted to engage said
limit member in one position of said shelf member.
21. A shelf assembly for a refrigerated compartment comprising:
a shelf support including a pair of spaced, generally parallel,
shelf support surfaces;
a shelf member slidably mounted for extension and retraction on
said shelf support, said shelf member including a shelf panel
having a perimeter edge, and a rim molded on said perimeter edge
from a moldable material, said rim including side portions
extending along opposite sides of said shelf panel, each side
portion including a slide surface slidably engaging one of said
shelf support surfaces, and a pair of spaced, depending guide
members molded in one piece with said rim and positioned on either
side of one of said shelf support surfaces to guide sliding
movement of said shelf member; at least one of said guide members
including a stop molded in one piece with said rim; and
said shelf support also including an elongated opening for
receiving and allowing movement of said stop when said shelf member
is slidably extended or retracted, and at least one limit surface
for engaging said stop member to limit at least one of the
extension or retraction of said shelf member.
22. The shelf assembly of claim 21, wherein said shelf support
includes a pair of spaced, parallel, L-shaped support brackets each
having a body and a laterally extending flange extending at a right
angle to said body, said flange having a generally horizontal top
surface forming said shelf support surface.
23. The shelf assembly of claim 22, wherein said flanges on said
brackets extend inwardly toward one another.
24. The shelf assembly of claim 22, wherein one of said guide
members of each side portion of said rim includes a portion molded
in one piece therewith which extends under said laterally extending
flange to restrict vertical movement of said shelf member with
respect to said L-shaped brackets.
25. The shelf assembly of claim 24, wherein at least one of said
brackets includes a limit member thereon, said stop adapted to
engage said limit member in one position of said shelf member.
26. The shelf assembly of claim 21, wherein said shelf support
includes an undersurface; one of said side portions including a
laterally extending, lift restraining member on one of said guide
members, said lift restraining member adapted to engage said
undersurface to restrict vertical movement of said shelf member
with respect to said shelf support surfaces.
27. A sliding shelf assembly for refrigerators comprising:
a generally planar shelf member having a top surface for supporting
articles to be refrigerated, and a perimeter edge;
a rim molded from a moldable material around said perimeter edge,
said rim including generally parallel side portions extending along
opposite portions of said perimeter edge of said shelf member, each
side portion including a slide channel molded therewithin, said
slide channels each defining a generally horizontal slide surface,
a molded guide member for guiding sliding movement of said shelf
assembly, and an opening through which a shelf support is received
for engagement with said slide surface; said guide member extending
downwardly from said slide surface to limit lateral movement of the
shelf support member when received in said slide channel, said
guide member including a laterally extending, lift restraining
member, said lift restraining member extending laterally such that
said lift restraining member is spaced beneath said slide surface
and is adapted to be positioned immediately adjacent and below an
undersurface on a shelf support member to limit vertical movement
of the shelf support member when received in said slide channel;
and,
a stop on said rim adapted to be received in an elongated opening
formed in the shelf support to limit sliding travel of said shelf
assembly when mounted on the shelf support.
28. A sliding shelf assembly for refrigerators comprising:
a generally planar shelf member having a top surface for supporting
articles to be refrigerated, and a perimeter edge;
a rim molded from a moldable material around said perimeter edge,
said rim including generally parallel side portions extending along
opposite portions of said perimeter edge of said shelf member, each
side portion including a slide channel molded therewithin, said
slide channels each defining a slide surface, first and second
molded guide members for guiding sliding movement of said shelf
assembly, and an opening through which a shelf support is received
for engagement with said slide surface; said first and second guide
members on each side portion being spaced laterally from and
extending parallel to one another and depending downwardly adjacent
said slide surface; and
a stop on said rim for engaging a portion of the shelf support to
limit sliding travel of said shelf assembly when mounted on the
shelf support.
29. The shelf assembly of claim 28, wherein each of said slide
channels is spaced from and extends generally parallel to said
shelf member.
30. The shelf assembly of claim 29, wherein each of said slide
channels is aligned with and below said perimeter edge of said
shelf panel.
31. The shelf assembly of claim 30, wherein said shelf member is
glass and said moldable material is a resinous thermoplastic
copolymer.
32. The shelf assembly of claim 28, wherein each of said slide
channels is adapted to receive a slide support flange of a support
bracket, each of said slide channels being oversized and larger
than said support flange to allow sliding movement
therebetween.
33. A sliding shelf assembly for refrigerators comprising:
a generally planar shelf member having a top surface for supporting
articles to be refrigerated, and a perimeter edge:
a rim molded from a moldable material around said perimeter edge,
said rim including generally parallel side portions extending along
opposite portions of said perimeter edge of said shelf member, each
side portion including a slide channel molded therewithin, said
slide channels each defining a slide surface, a molded guide member
for guiding sliding movement of said shelf assembly, and an opening
through which a shelf support is received for engagement with said
slide-surface; said guide member extending downwardly from and
laterally under said slide surface such that said guide member is
spaced beneath said slide surface and is addicted to be positioned
immediately adjacent and below a shelf support member to limit
lateral and vertical movement of the shelf support member when
received in said slide channel; and
a stop on said rim adapted to be received in an elongated opening
formed in the shelf support to limit sliding travel of said shelf
assembly when mounted on the shelf support, said stop molded
integrally on said molded guide member.
34. A shelf assembly for a refrigerated compartment comprising:
a shelf support including a pair of spaced, generally horizontal,
generally parallel, shelf support surfaces, a guide surface on each
shelf support surface extending at an angle to said shelf support
surface, an undersurface beneath each shelf support surface, and at
least one mounting member adapted to mount said shelf support in a
refrigerated compartment;
a shelf member slidably mounted for extension and retraction on
said shelf support, said shelf member including an article support
surface and a pair of spaced side members, said side members being
molded in one piece on said article support surface from a moldable
material and extending along opposite sides of said article support
surface, each side member including a slide surface slidably
engaging one of said shelf support surfaces, at least one of said
side members including a depending guide member adjacent said slide
surface to guide sliding movement of said shelf member, said one
guide member including a stop thereon, said guide member extending
along said guide surface to limit movement of said shelf member
with respect to said shelf support, said guide member also
including a laterally extending, lift restraining member, said lift
restraining member extending under and immediately adjacent said
shelf support undersurface and adapted to engage said undersurface
in the event said shelf member is lifted to restrict vertical
movement of said shelf member with respect to said shelf support;
said guide member further including a rigid member having a first
portion embedded within said one side member, and a second portion
positioned along said guide surface and adjacent said shelf support
undersurface to guide sliding movement and restrict vertical
movement of said shelf member, said second portion of said rigid
member including said stop thereon;
said shelf support also including an elongated opening for
receiving and allowing movement of said stop when said shelf member
is slidably extended or retracted, and at least one limit surface
for engaging said stop member to limit at least one of the
extension or retraction of said shelf member.
35. The shelf assembly of claim 34, wherein said first portion of
said rigid member extends generally parallel to said slide surface
of said one side member to resist withdrawal from said one side
member.
36. The shelf assembly of claim 35, wherein said rigid member is a
U-shaped insert, said second portion including an L-shaped portion
of said insert.
37. The shelf assembly of claim 36, wherein said shelf support
includes a pair of spaced, parallel support brackets, each bracket
having one of said shelf support surfaces and one of said mounting
members thereon; said L-shaped portion extending in the space
between said brackets, said stop including an edge of said L-shaped
portion; said shelf support including at least one cross member
extending between said brackets; said limit surface including a
limit member on one of one of said brackets and said cross member
for engagement by said edge of said L-shaped portion.
38. The shelf assembly of claim 34, wherein said rigid member is a
stud embedded in said slide surface of said one side member.
39. The shelf assembly of claim 38, wherein at least one of said
shelf support surfaces includes a slot forming said elongated
opening; said stud projecting into said slot; said slot having at
least one closed end defining said limit surface.
40. The shelf assembly of claim 39, wherein said stud includes
spaced, laterally extending flanges, one stud flange embedded in
said one side member, the other stud flange extending under said
shelf support surface.
41. The shelf assembly of claim 40, wherein said slot includes an
enlarged area for receiving said other stud flange therethrough.
Description
BACKGROUND OF THE INVENTION
This invention relates to shelving especially adapted for use in
refrigerator compartments, especially refrigerators for food
products, and more particularly, to a sliding shelf assembly for
refrigerators having improved weight supporting capabilities,
improved sliding movement, and an improved method for
manufacturing.
Many varieties of sliding refrigerator shelving have been used in
the past. Typically, such sliding shelves include a shelf panel
mounted for horizontal sliding extension toward the user through
the door opening of the refrigerator to provide better access to
items stored on the shelf or for ease in cleaning. One prior shelf
includes a plurality of preformed frame members assembled around a
shelf panel and slidably secured on appropriate support brackets.
In another, tracks on opposite side surfaces guide sliding movement
of the shelf panel.
In certain of the prior known sliding shelves, difficulty in
extending and retracting the shelf was experienced, especially when
the shelf was heavily loaded with articles for refrigeration. In
some cases, uneven extension required additional effort, while in
others, the support strength in the extreme extended position, was
less than desired.
In addition, many prior known sliding shelf assemblies required
manufacture from a number of individually fabricated pieces
increasing manufacturing time and expense. Such shelves would not
contain liquids if spilled, and thus would not limit contamination
of the refrigerator or cabinet in the event a container was
overturned. In many prior known molded shelves, specialized mold
apparatus was required and the appearance of the sliding shelf
assembly was often different from the standard, fixed shelves used
adjacent to the sliding shelves in the same refrigerator.
Accordingly, a need has existed for an improved sliding shelf
assembly for refrigerators which would control and help confine
spillage of liquids or other food items while providing improved
sliding characteristics even when heavily loaded, increased support
strength in both the extended and retracted positions, a similar
appearance to standard, fixed position shelving used in the same
refrigerator, and improved, simplified manufacturing techniques
reducing manufacturing time and expense.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a shelf assembly for
refrigerated compartments, and especially refrigerators for food
products, in which a shelf member is slidably mounted for extension
and retraction on a shelf support, the shelf member including side
members which are molded in one piece on an article support surface
from a moldable material while incorporating either a molded guide
member or an embedded insert which guides sliding movement and
restricts vertical movement of the shelf with respect to the
support. One of several varieties of a stop member for limiting
extension or retraction is included. The invention also encompasses
a manufacturing method including the provision of a rigid core
having a portion embedded within the molded slide member, which
core is withdrawn after molding to provide a slide channel avoiding
the necessity of assembling the slide member from multiple parts
and also allowing use of the same mold cavity used to form fixed
refrigerator shelf versions.
In one form, the invention is a shelf assembly for a refrigerated
compartment including a shelf support and a shelf member slidably
mounted for extension and retraction on the shelf support. The
shelf support includes a pair of spaced, generally horizontal,
generally parallel shelf support surfaces and a guide surface
extending at an angle to each shelf support surface. At least one
mounting member is adapted to mount the shelf support in a
refrigerated compartment. The shelf member includes a pair of
spaced side members molded in one piece on an article support
surface from a moldable material, the side members extending along
opposite sides of the article support surface. Each side member
includes a slide surface engaging one of the shelf support
surfaces. At least one of the side members has a depending guide
member adjacent the guide surface to guide sliding movement of the
shelf member, the guide member also including a stop. The shelf
support also includes an elongated opening for receiving and
allowing movement of the shelf when the shelf member is slidably
extended or retracted and at least one limit surface for engaging
the stop member to limit at least one of the extension and
retraction of the shelf member.
In preferred aspects of the invention, the guide member and stop
are molded integrally and in one piece with the side member while a
second guide member is also molded on each side member to confine
the shelf support surface for proper sliding movement. The guide
members and slide surface are defined by a slide channel which, in
the preferred form, is formed by the preferred method set forth
herein.
In other preferred aspects, the guide member and stop may be formed
by a rigid insert embedded within the molded side member during
molding and having a portion extending downwardly from the side
member along and under the shelf support to restrict sliding and
vertical movement of the shelf. Such rigid insert can be either a
U-shaped member or a headed stud.
Preferably, the shelf support includes a pair of L-shaped support
brackets, each including a vertical body and a laterally extending
flange, the flange having a top surface forming the shelf support
surface. The limit surface may be formed either on the L-shaped
bracket or on a cross member spacing the L-shaped bracket members
apart. In the version incorporating the headed stud guide member, a
slot is formed in the flange of the L-shaped bracket receiving the
stud for both guiding and limiting sliding movement.
In another aspect of the invention, a method for making a sliding
shelf includes the provision of a rigid core having a slide channel
forming portion thereon. The core is inserted in a mold apparatus
such that the slide channel forming portion is located in the mold
cavity. A slide member is molded from moldable material on an
article support surface in the mold cavity while embedding the
slide channel forming portion in the slide member. The molded slide
member is then removed from the mold cavity with the slide channel
forming portion remaining embedded within the slide member.
Thereafter, the slide channel forming portion of the core is
withdrawn from the slide member to form a channel within the slide
member, the channel adapted to receive a slide support for sliding
movement of the shelf.
In preferred aspects of the method, injectable polymeric material,
such as a thermoplastic copolymer, is injected around the slide
channel forming portion while a retaining portion of the core
extends out of the slide member to form an opening to the slide
channel. Preferably, the article supporting surface is formed by a
glass panel member having a perimeter edge simultaneously embedded
within the slide member when the core is embedded therein. The core
may then be rotated and slid out of the molded side member to
complete the manufacture.
In its various forms, the present invention provides numerous
advantages over prior known sliding shelf assemblies for
refrigerators. The shelf assembly includes molded side members
integrally incorporating a molded slide channel having guide
members which allow smooth, uniform sliding extension and
retraction of the shelf even when heavily loaded and without
bothersome ratcheting or stuttering during sliding movement. Such
construction maximizes available shelf space for storage while
maintaining smooth shelf operation. The molded rim effectively
controls and confines spilled liquids or other items on the shelf
and is tightly sealed to the shelf panel to prevent unsanitary
seepage between the rim and panel. The combination of support
brackets and molded slide surfaces along with guide members which
extend under the slide support surfaces prevent tipping, lifting or
vertical movement of the shelf to allow the support of greater
loads in both the extended and retracted positions. Manufacture of
the sliding shelf is simplified through the use of a mold apparatus
which allows embedding of a reusable core which can be withdrawn
from the molded shelf after molding to leave a molded slide channel
ready for installation on the shelf support. Alternately, rigid
inserts can be positioned in the mold cavity for embedding within
the molded shelf to provide the guide members and stops allowing
improved sliding movement. In addition, the method allows use of
the same mold apparatus used to manufacture fixed, stationary shelf
assemblies simply by the inclusion or omission of the core or rigid
inserts and substitution of appropriate fixed shelf support members
in the mold cavity.
These and other objects, advantages, purposes, and features of the
invention will become more apparent from a study of the following
description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top perspective view of a first embodiment of the
sliding shelf assembly of the present invention;
FIG. 2 is atop perspective view of the shelf support frame for the
shelf assembly of FIG. 1;
FIG. 3 is a side elevation of the shelf assembly of FIG. 1;
FIG. 4 is a fragmentary sectional view taken along plane IV--IV of
FIG. 3;
FIG. 5 is a fragmentary, plan view of a front corner of the shelf
assembly taken in area V of FIG. 1 with portions broken away;
FIG. 6 is a sectional side elevation of the front area of the shelf
assembly taken along plane VI--VI of FIG. 1;
FIG. 7 is a fragmentary, sectional view taken along plane VII--VII
of FIG. 3;
FIG. 8 is a sectional view taken along plane VIII--VIII of FIG.
1;
FIG. 9 is a fragmentary plan view of a rear portion of the shelf
assembly taken along plane IX--IX of FIG. 3;
FIG. 10 is a side view of a molded limit member for use with the
shelf assembly of FIG. 1;
FIG. 11 is an end elevation of the limit member of FIG. 10;
FIG. 12 is a sectional side elevation of the limit member of FIGS.
10 and 11;
FIG. 13 is a sectional view of the shelf assembly showing the limit
member inserted and taken along plane XIII--XIII of FIG. 4;
FIG. 14 is a side elevation of a second embodiment of the sliding
shelf assembly of the present invention;
FIG. 15 is a side elevation of the shelf assembly of FIG. 14 with
the sliding shelf member in extended position;
FIG. 16 is a fragmentary plan view of the shelf assembly of FIG.
15;
FIG. 17 is a fragmentary, sectional view taken along plane
XVII--XVII of FIG. 16;
FIG. 18 is a fragmentary, sectional view taken along plane
XVIII--XVIII of FIG. 16;
FIG. 19 is a fragmentary, sectional view taken along plane XIX--XIX
of FIG. 16;
FIG. 20 a fragmentary, sectional view taken along plane XX--XX of
FIG. 16;
FIG. 21 is a fragmentary, sectional view taken along plane XXI--XXI
of FIG. 16;
FIG. 22 is a top perspective view of a third embodiment of the
sliding shelf assembly of the present invention;
FIG. 23 is a fragmentary, exploded view of portions of the shelf
assembly of FIG. 22;
FIG. 24 is a fragmentary, sectional view taken along plane
XXIV--XXIV of FIG. 22;
FIG. 25 is a fragmentary, sectional view taken along plane XXV--XXV
of FIG. 22;
FIG. 26 is a top perspective view of the shelf assembly of FIG. 22
with the shelf member shown in extended position;
FIG. 27 is a fragmentary, side elevation taken along plane
XXVII--XXVII of FIG. 26;
FIG. 28 is a fragmentary, top perspective, exploded view of a
fourth embodiment of the shelf assembly of the present
invention;
FIG. 29 is a fragmentary, sectional view taken along plane
XXIX--XXIX of FIG. 28;
FIG. 30 is a top perspective view of the shelf assembly of FIG. 28
showing the shelf member in extended position;
FIG. 31 is a fragmentary, sectional view taken along plane
XXXI--XXXI of FIG. 30;
FIG. 32 is a fragmentary, sectional view taken along plane
XXXII--XXXII of FIG. 31;
FIG. 33 is a top plan view of a core member used in molding the
shelf assemblies of FIGS. 1-21;
FIG. 34 is a side elevation of the core member of FIG. 33;
FIG. 35 is an end elevation of the core member of FIGS. 33 and
34;
FIG. 36 is a sectional view of a preferred mold apparatus for
making the shelf assemblies of FIGS. 1-21; and
FIG. 37 is a fragmentary, sectional view of the shelf member of
FIGS. 1-21 after molding but before removal of the embedded
core.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings in greater detail, FIGS. 1-13
illustrate a first embodiment 10 of a sliding refrigerator shelf
assembly according to the present invention including a shelf
member 11 having a generally planar shelf panel 12, a molded,
resinous perimeter rim 14 circumscribing shelf panel 12, and a
rigid, shelf support frame 16 (FIG. 2) slidably supporting shelf
member 11 for sliding movement between a retracted position (solid
lines in FIG. 1) and an extended position (phantom lines in FIG. 1)
in a refrigerated compartment such as a refrigerator for food
products. Sliding shelf assembly 10 is preferably cantilevered
forward by support frame 16 from a pair of spaced, vertical support
tracks S (FIG. 1) mounted within the refrigerated compartment, each
support track S including a plurality of aligned, vertical slots 15
adapted to receive mounting hooks 30, 32 from support frame 16 as
described hereinafter. Shelf 10 may, of course, be made in various
widths, narrower or wider than that shown in FIG. 1, to accommodate
desired refrigerator cabinet widths and various spacing of tracks
S.
As is best seen in FIGS. 2 and 3, shelf support frame 16 includes a
pair of laterally spaced side support brackets 20a, 20b, each of
which has an inverted L shape when viewed in cross section as shown
in FIG. 4. Brackets 20a, 20b each include a generally vertically
extending, elongated body 22, and a laterally inwardly extending
support flange 23 extending at a right angle to body 22 and having
a generally planar shelf support surface 24 along the top edge of
the bracket for the majority of its length. A front, reduced height
portion 26 on each bracket extends forwardly below the level of
shelf support surfaces 24 to provide an access area for
telescopingly inserting shelf member 11 thereon as described below.
The rear end 28 of each L-shaped bracket 20a, 20b includes a
mounting hooks 30, 32. Hooks 30, 32 are adapted to be received in
slots 15 of vertical support tracks S (FIG. 1) when shelf assembly
10 is mounted in a refrigerated compartment as mentioned above.
Each rear mounting portion 28 includes an offset upper flange 34
adapted to be received within a molded recess at the rear of molded
rim 14 on shelf 11 as discussed below. The top surfaces 24 of
support flanges 23 are preferably co-planar and horizontal when
supported in the refrigerator. Side edges 25 of flanges 23 and the
side surfaces of bodies 22 act as guide surfaces for shelf 11
during sliding movement. The body portion 22 of each bracket 20a,
20b also includes a circular opening 35 adapted to receive a slide
limiting insert 72 as described below to restrict the forward
sliding movement of shelf member 11 on the shelf support frame 16.
A pair of spaced circular apertures 37 allow the brackets to
receive rivets or other fasteners for securing a pan or crisper
support P (shown in phantom in FIG. 2) if desired. Support P would
allow suspension of a slide-out pan or storage bin for meats,
vegetables and produce, or the like.
Brackets 20a, 20b are preferably supported parallel to one another
in spaced lateral positions by a pair of rigid cross members 36,
38, each of which also has an L-shaped cross section for strength
and rigidity. Brackets 20a, 20b are preferably welded to the ends
of cross members 36, 38 to form a rigid framework enabling the
support of shelf member 11 in both extended and retracted position
either when fully loaded with items to be refrigerated or when
empty. Cross members 36, 38 define an opening 39 therebetween in
the framework. Mounting hooks 30, 32, when engaged with vertical
tracks S, fully support the shelf without the necessity of any
additional supports extending from the sides of the refrigerated
compartment into contact with brackets 20a, 20b or the like. Each
bracket and cross member is preferably stamped from steel. Shelf
support frame 16 preferably is powder-coated with an epoxy
polyester coating, preferably white in color, sold under Product
No. 071-30-06 by Herberrs Powder Coatings Inc., of Hilliard, Ohio.
The powder coating provides both a reduced friction, lubricous
surface for shelf member 11 to slide on as well as providing
protection from corrosion due to contact with spilled liquids,
water and the like. Preferably, shelf support surfaces 24 are
co-planar as shown in FIG. 2, although they could be positioned in
offset planes depending on the design of the shelf member fitted
thereon.
Referring now to FIGS. 1 and 3-9, shelf panel 12 is preferably a
planar sheet of light transmitting material, such as optically
clear tempered glass, to enhance light distribution through the
refrigerated compartment. Panel 12 includes a perimeter edge 18
(FIGS. 4 and 6) which is embedded and secured within molded rim 14
generally above spaced support flanges 23 on brackets 20a, 20b in
shelf support frame 16 as shown in FIG. 4. Rim 14 is preferably
molded around the entire perimeter edge 18 of shelf panel 12. Rim
14 extends above panel 12 around the entire panel to confine spills
and is molded for tight engagement and liquid sealing with panel 12
to prevent seepage under the rim and between the glass and rim as
is explained in co-pending, commonly assigned United States patent
application Ser. No. 07/665,661, filed Mar. 7, 1991, entitled
MOLDED REFRIGERATOR SHELF, now issued as U.S. Pat. No. 5,362,145,
the disclosure of which is hereby incorporated by reference herein.
Molded rim 14 includes an integral front strip 40, integral rear
strip 42 and parallel side strips or portions 44, 46, all of which
are molded in one piece on the shelf member 12 in a single molding
operation, as is explained more fully below. The front, rear and
side portions 40, 42, 44, 46 of molded rim 14 each include molded
portions 14a, 14b, 14c (FIG. 6) which embed and envelope three
sides or surfaces of the perimeter edge 18 of panel 12 to securely
retain the panel in the shelf member.
Each molded side portion 44, 46 includes an integral, substantially
closed, slide channel 48 generally vertically aligned with the
perimeter edge 18 of shelf panel 12 but spaced therebelow by
intermediate molded portions of side portions 44, 46, as shown in
FIG. 4. Each slide channel 48 defines a pair of laterally spaced
outer and inner guide flanges 50, 52 which depend downwardly and
are generally flush with the side surfaces of side portions 44, 46.
Inner guide flange 52 also includes an integral laterally outwardly
extending flange 54 which extends under substantially the full
extent of flange 23 on L brackets 20a, 20b. A stop member 56 is
molded integrally with and depends downwardly from flange 54 at the
rear of the shelf for engagement with shelf support frame 16 as is
explained more fully below. The upper surface 58 of slide channel
48 is generally horizontal and parallel to the perimeter 18 of
shelf panel 12 and provides a slide surface adapted to engage the
top surface 24 of flange 23 to allow sliding movement of the shelf
member 11 with respect to support frame 16. The front end 55 of
slide channel 48 is closed (FIG. 5) while the rear of the channel
opens into the area beneath rear strip 42 to allow insertion of
support flanges 23. As will be understood from FIGS. 4 and 6, the
size of slide channel 48 is oversized and larger than the size of
flange 23 and the upper portion of vertical body 22 of brackets
20a, 20b to provide sufficient clearance for ease in sliding action
while maintaining lateral guidance via flanges 50, 52 with
restriction against vertical movement of the shelf away from
brackets 20a, 20b via flanges 54.
As seen in FIGS. 1, 5 and 6, the front strip 40 of molded rim 14
includes an outwardly and downwardly extending flange 60 including
an indicia area 62 for molding or imprinting of appropriate
information, trademarks or the like. If desired, area 62 may
include a recess for such information. Flange 60 includes sides 64
which form a downwardly opening enclosure with flange 60 to house
and shield the projecting ends 26 of frame 16 when the shelf member
11 is received thereover. The lowermost edge 66 of front strip 40
provides a convenient area for grasping the shelf for extension and
retraction.
As is best seen in FIGS. 1, 3 and 7-9, rear strip 42 of molded rim
14 extends upwardly and rearwardly along surface 68 and includes
sides 70 forming a generally rearwardly opening enclosure which
covers offset edges 34 of rear mounting portions 28 on brackets
20a, 20b when the shelf member 11 is retracted.
Preferably, rim 14 is formed from a moldable, resinous material
such as a thermoplastic copolymer, most preferably TENITE.TM.
polypropylene sold under Product No. P5M4K-007 by Eastman Plastics
of Kingsport, Tenn. Such material is a combination of ethylene and
polypropylene, although other structural, resinous plastics, such
as ABS or polyvinylchloride could be used. Preferably, a coloration
pigment may be added to the moldable plastic used for molding rim
14 prior to molding to provide a desired color to the rim. For
example, titanium dioxide may be added for a white coloration.
While the liquid-tight seal formed between molded rim 14 and glass
shelf panel 12 performs well, depending on the specific resinous
plastic chosen, one may wish to enhance that seal by coating
perimeter edge 18 of the glass panel 12 in the areas to be engaged
by the molded rim with a primer layer or coating prior to molding
of the rim. Such primer layer or coating is preferably a heat
activatable, resinous material which promotes and facilitates the
adhesion of the rim material to the glass shelf member 12.
With reference to FIGS. 3, 4 and 10-13, a resilient, limit member
or insert 72 is preferably received in opening 35 of each bracket
side 22 to limit the forward travel of the sliding shelf member 11
when extended. Preferably, insert 72 is molded from a resinous
plastic material such as acetal, available from E. I. DuPont de
Nemours Co., Wilmington, Del., and includes a head 74 and a hollow,
cylindrical body 76 extending perpendicularly from the underside of
head 74. Body 76 includes a central, circular opening 77 and is
notched at 78 to receive the thickness of bracket body 22 when the
insert is received in aperture 35, as shown in FIG. 13. As will be
understood from FIG. 13, the height and length of body 76 is
sufficient to extend into the path of molded stop 56 when insert 72
is received in aperture 35 such that further forward sliding
movement of shelf member 11 is limited by the engagement of stop 56
and body 76. The resiliency of body 76 allows it to compress and
slide through aperture 35 and snap outwardly into the position
shown in FIG. 13. Moreover, should shelf member 11 be pulled
outwardly with significant force, body 76 will bend slightly to
absorb some of the energy as shelf member 11 is stopped against the
limiting insert.
As will be best understood from FIGS. 1-3, after manufacture, shelf
member 11 is slidably telescopingly mounted on inwardly extending,
co-planar flanges 23 of frame 16 from the front edges of those
flanges. Flanges 23 are received in the rearwardly opening slide
channels 48 and shelf 11 is slid rearwardly until the inside
surface of rear strip 42 is received against offset areas 34 of
rear portions 28 of brackets 20a, 20b. Thereafter, limiting insert
72 is pushed into place through apertures 35. Forward extension of
shelf member 11 is obtained by pulling on lip 66 of front strip 40
typically with a pull effort of 1 to 2 pounds, while guide members
50, 52 guide the sliding motion of slide surface 58 on flanges 23.
Forward extension of shelf member 11 is limited by the engagement
between stops 56 and inserts 72, as described above. In the
extended position, items can be supported on the forward edge of
shelf 12 without fear of the shelf member 11 tipping forwardly and
spilling the item due to the extent of flanges 54 under flanges 23
which restrict vertical movement of the shelf away from the shelf
support frame 16. Shelf member 11 may then be retracted by pushing
it inwardly using front strip 40 until rear strip 42 engages offset
portions 34 of rear mounting portions 28 as shown in FIG. 8. The
vertical height of rear strip 42 helps to catch and support any
taller items which might tip rearwardly during sliding movement or
storage of items on the refrigerator shelf. Preferably, shelf
support frame 16 allows shelf assembly 10 to be vertically adjusted
within the refrigerator compartment on support tracks S. As noted
above, hooks 30, 32 are adapted for releasable engagement with
shelf tracks S to suspend the brackets, support frame and shelf
assembly. The shelf assembly may be positioned at any one of a
plurality of locations corresponding to the locations of the
aligned slots 15 in the tracks. The overall size of assembly 10 is
preferably slightly smaller than the inside dimensions of the
refrigerated compartment in which it is used to provide air
circulation space between the sides 22 of brackets 20a, 20b and the
sidewalls of the refrigerator as well as between rear strip 42 and
the rear wall of the refrigerator. Further, the overall length of
shelf member 11 is determined to provide air circulation space
between the front edge and the door of the refrigerator (not
shown).
With reference to FIGS. 14-21, a second embodiment 100 of the
sliding shelf assembly for refrigerated compartments is
illustrated. Shelf assembly 100 is similar to assembly 10 but
includes a shelf member 101 of slightly differing configuration
having a molded stop 122 adapted for engagement with a cross member
on the shelf support frame 130, as explained more fully below. As
shown in FIGS. 14-16, shelf member 101 includes a generally planar
shelf panel 102, preferably formed from optically clear tempered
glass and an upstanding molded rim 104 circumscribing the entire
perimeter edge 106 of shelf panel 102 and forming a liquid-tight
seal therewith. Rim 104 includes parallel front and rear portions
108, 110 and parallel side portions 112, all of which are molded
integrally and in one piece onto the perimeter edge 106 of panel
102 in a suitable mold apparatus, as explained below. Just as in
shelf member 11, molded .rim 104 includes an integral slide channel
114 (FIG. 19) molded beneath perimeter edge 106 to include spaced,
lateral outer and inner guide flanges 116, 118 and a laterally
inwardly extending flange 120 extending from guide flange 118. As
shown in FIGS. 14, 15, 20 and 21, an elongated stop member 122 is
molded integrally with and depends downwardly from the bottom
surface of flange 120 at a position flush with the inner side of
side portion 112. Stop 122 tapers rearwardly such that its bottom
edge is inclined upwardly toward the rear of shelf 101 to enable
telescopic mounting of the shelf member on support frame 130. The
forward edge 124 of stop 122 extends downwardly a distance
sufficient to engage the rear edge of a cross member 134 on the
support frame, as explained below. Shelf member 101 may be extended
and retracted by grasping the downwardly extending lip 126 on front
portion 108 as shown in FIG. 20. Just as in assembly 10, slide
channel 114 is oversized and larger than the support flange 138
from support bracket 132 adapted to be fitted therewithin to allow
ease in sliding movement. Likewise, flanges 116, 118 guide such
movement while lower flange 120 prevents lifting or tipping of the
shelf when extended or retracted.
As will be understood from FIGS. 14-16, a shelf support frame 130
similar to frame 16 in assembly 10 is adapted for use with shelf
member 101. Frame 130 includes a pair of L-shaped support brackets
132 which are spaced laterally and formed into a rigid framework by
front and rear L-shaped cross members 134, 136. Each bracket 132
includes an inturned, generally planar, elongated flange 138. As
shown in FIG. 21, flanges 138 are received in the rearwardly
opening slide channels 114 such that the top surfaces of flanges
138 engage slide surfaces 119 in the slide channels to allow
extension and retraction of shelf 101. Forward sliding movement of
shelf 101 is limited by engagement of front edge 124 of stop 122
with the rear facing edge of front cross member 134 as shown in
FIG. 20. During assembly, the clearance provided by the enlarged
size of slide channel 114 and the camming action provided by
inclined bottom surface of stop 122 allow shelf 101 to be cammed
over cross member 134 until the front edge 124 is received behind
the cross member. As in assembly 10, brackets 132 also include
mounting hooks 140 for mounting the assembly in a desired but
vertically adjustable position on vertically extending support
tracks such as those shown at S in FIG. 1. Also, molded rim 104 is
preferably formed from a thermoplastic copolymer of ethylene and
polyethylene, preferably TENITE.TM. polypropylene P5M4K-007 sold by
Eastman Plastics. Similarly, frame 130 includes brackets and cross
members stamped from steel and welded together and powder-coated
with epoxy polyester available from Herberts Powder Coatings Inc.
of Hilliard, Ohio, under Product No. 071-30-06.
As shown in FIGS. 22-27, a third embodiment 150 of the sliding
shelf assembly is illustrated where like parts are indicated by
like prime numbers. Embodiment 150 preferably includes a modified
shelf member 160 and a rigid steel and epoxy polyester
powder-coated shelf support frame 130'. Frame 130' is substantially
similar to shelf support frame 130 except for the addition of a
downwardly bent limit flange 152 formed in support flange 138' and
an upwardly extending limit stud 154 aligned with flange 138' in
rear cross member 136'.
Modified shelf member 160 includes a preferably optically clear
tempered glass shelf panel 162 and a molded rim 164 circumscribing
the perimeter edge of panel 162 as in shelf members 11 and 101. As
shown in FIGS. 22 and 26, molded rim 164 includes parallel front
and rear portions 170, 172, and parallel side portions 174, 176,
all molded in one piece around the entire panel 162 such that the
perimeter is sealingly embedded therein. Preferably, molded rim 164
is also formed from a thermoplastic copolymer of ethylene and
propylene. Instead of the inclusion of an integral, molded slide
channel beneath the perimeter edge 166 of panel 162, however, shelf
member 160 includes rigid, downwardly depending, U-shaped inserts
168 embedded in the molded rim.
Rigid inserts 168 are insert molded in spaced pairs in the lower
sliding surfaces 175, 177 of side portions 174, 176 generally
vertically aligned with the perimeter 166 of panel of 162, as shown
in FIGS. 24 and 25. Inserts 168 are U-shaped in section and include
upper and lower flanges 178, 180 joined by flange 182. When
embedded within the side portion of the molded rim, flange 178 is
spaced below perimeter edge 166 and extends generally parallel
thereto to resist removal of the insert from the molded side
portion. Flange 182 extends generally perpendicular to the
perimeter edge 166 while flange 180 is generally parallel to flange
178 and panel 162 but spaced below sliding surface 175, 177 such
that it extends around and under flange 138' from the shelf support
frame. Accordingly, flanges 182 provide lateral guidance during
sliding movement of shelf member 160 on flanges 138', while flanges
180 resist tipping and lifting of the shelf member 160 from the
support frame.
As will be understood, the rear edge of flange 180 on the rearmost
insert 168 is adapted to engage limit stud 154 to limit rearward
movement of the shelf member 160 on the support frame. Likewise,
the forward edge of flanges 180 of the same rearmost inserts 168
are adapted to engage limit members 152 to limit further extension
when the shelf is pulled outwardly and extended. The area beneath
flanges 138' and between limit members 152, 154 therefore defines
the extent of sliding movement of shelf assembly 150 (see distance
M in FIG. 23). However, in the extended position shown in FIG. 26,
items for refrigeration are fully and adequately supported even on
the outer end of the shelf due to the horizontal extent of flanges
138' and the vertical tipping and lifting restriction provided by
flanges 180 of inserts 168. Assembly of shelf member 160 on rigid
frame 130' is accomplished by telescoping shelf member 160 over
flanges 138' with the flanges 180 of inserts 168 in the positions
shown in FIGS. 24 and 25 before limit members 152 are bent
downwardly from the support flanges 138'. After the shelf member
160 is in the position shown in FIG. 22, limit members 152 are bent
downwardly to confine the shelf as described above.
As shown in FIGS. 28-32, a fourth embodiment 200 of the sliding
shelf assembly of the present invention is illustrated where like
parts are indicated by like numerals with the addition of double
primes thereon. Shelf assembly 200 includes shelf member 201
slidably mounted for extension and retraction on a rigid shelf
support frame 202. Shelf support frame 202 is similar to shelf
support frames 130 and 130' and includes L-shaped support brackets
132" spaced by rigid cross members 134" and 136". Rear cross member
136" includes a slide limiting stud 204 (FIGS. 31 and 32) which
restricts rearward sliding travel of shelf member 201 on the
support frame as explained hereinafter. Instead of bent limit
member 152 as in support frame 130', however, shelf support frame
202 includes elongated, keyhole-shaped guide slots 206 extending
through support flanges 138". Each guide slot 206 includes parallel
side edges, a closed forward end 208 and an enlarged opening
forming a closed, rear end 210. Brackets 132" also include mounting
hooks 140" for securing the shelf support frame 202 and supported
shelf member 201 on suitable vertical support tracks such as those
shown at S in FIG. 1. The entire rigid frame 202 is preferably
powder-coated with epoxy polyester as in the earlier embodiments
10, 100, and 150.
Shelf member 201 includes an optically clear, tempered glass panel
211 and a molded rim having parallel front and rear sections 212,
214 and parallel, opposed side portions 216, 218. Each side portion
includes an integral, molded guide flange 220 (FIGS. 29 and 31) on
the outer side for engaging the vertical side surface of brackets
132" to guide sliding movement. In addition, lower slide surfaces
222 of side portions 216, 218 include a pair of spaced,
double-headed stud inserts 224 embedded therewithin generally in
the center and at the rear of each side portion. Each stud insert
224 includes cylindrical body 226 adapted to be received through
and between the parallel side edges of slots 206 to guide the
sliding movement of the shelf member 201 in conjunction with
flanges 220. At the upper end of cylindrical body 226 is a
disc-shaped head 228 embedded within side portion 226 at a position
spaced below the perimeter edge of glass panel 211 to resist
withdrawal of the stud. At the lower end of body 226 is a similar
disc-shaped head 230 which extends below support flange 138" and
slots 206.
As will now be understood from FIGS. 28-32, when inserts 224 are
embedded in the sliding surfaces 222 of side portions 216, 218 as
shown in FIGS. 29, 31 and 32, shelf member 201 may be mounted on
shelf support frame 202 by placing shelf member 201 in registry
with support flanges 138" such that heads 230 of inserts 224 are
aligned with enlarged openings 210. Shelf member 201 is then moved
downwardly such that sliding surfaces 222 engage support flanges
138" while heads 230 extend through openings 210 of slots 206.
Thereafter, shelf member 201 may be grasped and slid forwardly on
its slide support surfaces and flanges 138" until bodies 226 of
inserts 224 engage forward ends 208 of slots 206 to limit further
extension. Likewise, rearward movement of the shelf is limited by
engagement of heads 230 with studs 204 on cross member 136" in the
retracted position of the shelf. In either case, items to be
refrigerated are fully and adequately supported on panel 211 while
flanges 220 and bodies 226 guide the sliding movement and heads 230
prevent lifting of the shelf member 201 from the support frame 202
in all positions including the extended position except the
retracted position shown in FIGS. 31 and 32.
With reference to FIGS. 33-38, the preferred method for
manufacturing the shelf members used in the shelf assemblies 10 and
100 will be understood. The manufacturing method incorporates the
use of a reusable, rigid mold insert or core 250 which is generally
similar in shape to L-shaped support brackets 20a, 20b and 132.
Core 250 is preferably formed from a ferro-magnetic material such
as steel, preferably includes a corrosion preventing coating such
as zinc-dichromate, has a generally planar, retaining body 252 and
an integral, laterally extending flange 254 extending along the
full length of body 252 at one edge. Flange 254 defines a slide
channel forming portion which tapers to a thinner, free end edge
256. Core body 252 includes a series of spaced, apertures 258 used
in manufacturing the core, as well as positioning apertures 260
adapted to receive positioning pins 314 for precisely locating the
core within a mold apparatus as explained below.
With reference to FIG. 36, a preferred mold apparatus 275 for
molding the shelf members 11, 101 is shown. Mold 275 includes a
lower mold section 280 including a central recess 282 receiving a
vertically reciprocable pressure pad or plate 284 preferably
mounted on springs and guide bolts (not shown) and having a glass
support surface 286. Lower section 280 also includes lateral slide
recesses 290 at either side. Cooperating with lower mold section
280 is an upper mold section 292 having a lower surface 293
defining a parting line and an upper glass engaging and clamping
surface 294. Together, glass engaging surface 294 of upper mold
section 292 and glass support surface 286 of pressure pad 284
support, clamp and hold a planar sheet of glass such as panel 12,
102, 162 or 211 described above.
At either side of mold 275 in side recesses 290 is a slide 306
mounted on a cylinder rod 308 of a pneumatic or hydraulically
operated fluid cylinder (not shown). Rod 308 is preferably fixed in
a stationary position by threaded end 309 while slides 306 and
fluid cylinders move inwardly and outwardly together when the fluid
cylinders are operated. In combination, lower mold section 280,
upper mold section 292, pressure pad 284 and slides 306 define a
pair of mold cavities 312 adapted for forming the side portions 44,
46 or 112 of shelf members 11,101 described above. Mold cavities
312, of course, extend continuously into other portions of the
upper and lower mold sections to define extensions thereof for
forming the front and rear portions 40, 42 of the shelf members as
is conventionally known in the molding industry.
As shown in FIG. 36, mold insert cores 250 are adapted for
insertion with their slide channel forming sections 254 positioned
within mold cavities 3 12, their retaining portions 252 extending
outwardly and downwardly from the mold cavities for engagement by
slides 306 including spring-biased positioning pins 314. Pins 314
extend through positioning apertures 260 after cores 250 are
positioned against the side surface of the lower mold section and
held in place by magnets 316. Subsequently, as the fluid cylinders
are activated to move slides 306 inwardly against the cores 250,
pins 314 accurately and precisely position the cores with respect
to the perimeter edge of glass sheets 12, 102 such that the glass
sheet perimeter edge will be spaced above section 254 and be
properly embedded within the mold material in cavity 312 while
retaining portion 252 will extend downwardly out of the molded rim
portion, as shown in FIGS. 36 and 37.
Using the mold 275 as described above, the manufacturing process
for producing shelf members 11, 101 will be understood. Initially,
upper mold section 292 is moved away from lower mold section 280.
Either manually or with a robot arm preferably having vacuum cups
holding glass sheet 12, 102 and a pair of spaced cores 250 thereon,
the glass panel is moved into the mold and loaded on glass support
surface 286 of pressure pad 284. The perimeter side edges of the
glass sheet extend into mold cavities 312. Simultaneously, both
core inserts 250 are loaded manually or with the same robot arm by
swinging them in against the side surfaces of the lower mold
section beneath mold cavities 312 until magnets 316 grasp and hold
the cores in position as shown in FIG. 36. The robot arm is moved
out of the open mold assembly followed by closing of the mold. Both
the upper and lower mold sections are preferably heated or cooled
as necessary via internal fluid lines and heated or cooled water
pumped therethrough to maintain a constant temperature during the
molding operation. After closure of the upper and lower mold
sections, with glass panel 12, 102 being held between the clamping
surfaces 294 of the upper mold section and the glass support
surfaces 286 of resiliently mounted pressure pad 284, the fluid
cylinders are activated to move slides 306 inwardly. During such
movement, spring-biased positioning pins 314 engage tapered holes
260 at two locations on each core 250 to finally and precisely
locate the cores such that slide channel forming sections 254 are
precisely positioned with respect to the perimeter edge of glass
panel 12, 102 in the mold cavities.
After loading of the glass and cores, the preferred thermoplastic
copolymer of ethylene and propylene mentioned above is injected
into mold cavities 312. Injection is preferably made using a
conventionally known hot runner injection system. Alternately,
conventionally known sub gating, cold drop gating or edge gating
injection methods can be used. Injection of the molten moldable
material which is preferably heated during injection is made
through small orifices, preferably at two or four positions on the
underside of the front and rear portions of the shelf members such
as at position A shown in FIG. 5. After injection, the moldable
material is allowed to solidify and cure during a dwell time
preferably of 10 to 15 seconds. Thereafter, slides 306 are moved
outwardly by their associated fluid cylinders and the mold 275 is
opened by raising the upper mold section 292. During such movement,
an ejector plate (not shown) engages suitable stops positioned to
halt further movement of the ejector plate while upper mold section
292 continues to its final position. Consequently, the shelf
assembly including the molded side portions in cavities 312 and
glass plate 12, 102 is moved downwardly away from the mold cavity
portions in upper mold half 292 while being held by suitable vacuum
cups (not shown) on upper mold section 292. Simultaneously, other
vacuum cups (not shown) on lower mold section 280 are opened to
atmosphere to release the glass panel. Subsequently, the robot arm
is moved into the open mold assembly carrying a new glass panel and
a fresh pair of spaced reusable cores 250 to retrieve the completed
shelf member and position the new glass panel and core members as
described above.
After removal of the molded shelf member from the mold 275, cores
250 remain embedded within the molded side portions 44, 46, 112, as
shown in FIG. 37. While the moldable material is still warm and
relatively flexible and pliable, cores 250 are slid out of the
slide channels 48, 114 in the molded side portions using a rolling
motion, either manually or in a fixture. If a fixture is used, the
shelf assembly is mounted upsidedown and pneumatic or hydraulic
cylinders are moved to engage the outer surfaces of the cores to
move them in a rolling motion in the direction shown by the arrow
in FIG. 37. Removal of the slide channel forming sections 254 of
cores 250 leaves slide channels 48, 114 integrally molded as
described above for receipt of the support surfaces of the shelf
support frame in the manner indicated.
Manufacture of the shelf members 150, 200 may be accomplished in a
similar mold apparatus to that shown at 275. Instead of positioning
reusable cores 250 in the mold cavities, rigid inserts 168 or 224
are positioned to extend into the mold cavities for proper
embedding within the molded rim portion in the manner described
above.
As will also be understood, mold 275 may also be used to form a
fixed, stationary shelf wherein fixed support brackets similar to
brackets 20a, 20b or 132 are substituted for cores 250 in mold
cavities 3 12. Such brackets remain in the molded side portions
after removal from the mold. Accordingly, the molded sliding
shelves made according to this method will have substantially the
same overall appearance as a fixed shelf when made in the same mold
apparatus.
While several forms of the invention have been shown and described,
other forms will now be apparent to those skilled in the art,
therefore, it will be understood that the embodiments shown in the
drawings and described above are merely for illustrative purposes,
and are not intended to limit the scope of the invention which is
defined by the claims which follow.
* * * * *